Revert "Use true residual in exit condition of GMRES"
Revert "Use true residual in exit condition of GMRES"

This reverts commit 54c9607d36716af0b53cf35e0f0f36b21b96db50.

The change made gmres prohibitively expensive. It made less iterations,
but most of the iterations were spent outside of the inner gmres loop.

ddemidov/amgcl,ddemidov/amgcl,huahbo/amgcl,ddemidov/amgcl,huahbo/amgcl,dondieselkopf/amgcl,dondieselkopf/amgcl,dondieselkopf/amgcl,huahbo/amgcl,ddemidov/amgcl